Investigation into the environmental factors that drive microbial diversity in the soils of the Miers Valley, Mt Erebus, Bratina Island and Beacon Valley

Entry ID:
K023_2005_2007_NZ_1

Summary

Abstract:
Modern molecular phylogenetics, in conjunction with sensitive mineral surface geochemical analysis, was used to determine the quantitative and qualitative distribution of micro-organism in Dry Valley soils, the key environmental factors that determine microbial distribution and what the role of micro-organism in community structure are. Several sites were sampled including Mt Erebus, the Miers ... Valley, Bratina Island and Beacon Valley. At Mt Erebus, the site was probed for soil temperatures and the areas hot spots were mapped. The temperature, pH and soil moisture was measured over three transects and the soil was sampled at intervals along each transect. A temperature logger with two probes, one at 4cm depth and the other on the surface was installed for one year. At the Miers Valley, a survey of hypoliths was conducted to gain a quantitative estimation of habitat and biomass values. Hypolith dimensions (cm2), weight of the hypolith rock (g), gross weight of the community (g), the depth of rock insertion (mm) and the depth of penetration (mm) were all recorded. Environmental data (temperature, humidity and irradiance levels) of hypoliths was also recorded with probes at the underside of the hypolith (3cm deep), the soil surface, open mineral soil (3cm) and non-translucent rock (3cm). Photographs were taken of the hypoliths and samples were collected for phylogenetic analysis, pigment spectrophotometric analysis and ATP analysis. A transect was established and soil samples were collected at intervals along the transect. An area with several (>48) seal carcases was surveyed with transects running through individual carcasses. Transects were described, sampled at intervals, pH measured, CO2 profiles determined, the relative humidity and temperature under the carcass measured, sampled for RNA analysis and microscopy and DNA samples were extracted. Other seal carcasses were sampled for carbon dating. Two experiments were set up: 1) Hypolith growth experiment to determine if soils are capable of seeding de novo hypoliths and 2) DNA longevity was determined in soil next to a hypolith sample using a clonesaver card cut into 9 bits. Soil types were also plated onto media for isolation of certain bacteria. At Bratina Island, two ponds (P70 and Orange) were sampled, and temperature and pH recorded. A short visit was made to the Beacon Valley where soils were sampled across a 25m transect for comparison. Samples (comprising DNA extracts, soil samples, mummified seal tissue samples, RNA later-stabilised soil samples, rock samples, hypolith samples and culture plates) collected from the Miers and Beacon Valleys were returned to the University of Waikato.

Quality
In the 2005-2006 season, samples of soil, sediment and water were collected from Tramway Ridge, Bratina Island meltwater ponds and in the Miers Valley. A set of soil and hypolith samples are held in South Africa.

In the 2006-2007 season, samples were collected from Tramway Ridge, Mt Erebus, the Miers Valley and Beacon Valley. Samples consisted of soil, ... hyperrhic measurements, seal samples, cyanbacterial mats and hyperliths. A small number of samples are held in South Africa.

All of the collected samples are stored at the University of Waikato, Hamilton New Zealand in a PC2 containment facility. Various amounts of the samples are held at the University of Western Cape, Cape Town, South Africa and is indicated below. The samples are stored at -80C. The samples were used for DNA analysis and this analysis uses very little material. Therefore, most if not all, of the samples still exist.